Don't know if this has been suggested before. It shouldn't be very difficult to implement into the game.
Green Normal Slimes- no change. Drops green slime balls
Red fire Slimes- When they hop around, they leave a trail of fire. When you destroy a large slime(or bigger) it explodes with a fireball dealing fire damage and setting players and mobs on fire, and splits into smaller red slimes. Of course the fire slime is immune to fire. Drops Red Slime Balls.
Blue Ice Slimes- As they hop around. They leave snow on the ground where they have been. Large blue slimes create blocks of ice in the spot where it is killed, and splits into smaller blue slimes. Ice and snow will melt instantly if generated too near a torch or lava. Drops Blue Slimeballs
Slimeballs can be thrown(like eggs and snowballs)
Red Slimeballs can be thrown to start fires where they land. If thrown at a mob, it sets it on fire.
Blue Slimeballs, if thrown into water, freeze the water into ice. Or it creates snow if they hit land. If thrown at a mob, it freezes it solid until a torch or lava melts it.
Green Slimeballs cannot be thrown (or has no special effect if they can) and are used to craft red and blue together. Craft Red+Green+Blue. This makes an explosive block that can be placed like TNT, but doesn't destroy blocks. It only deals damage to mobs.
EDIT:Adding Spawn limits.
Blue Slimes only spawn in Snowy Biomes, both underground(all day and night) and on the surface,(only at night) light level less than 7(or whatever moonlight is)
I wanted to give a strong application for each type. Creating Ice is a strong ability. theres no other way to do this. First pour a water bucket where you want it to go, then throw a blue slimeball into it to freeze it into ice.
Red slimeballs would be a long range version of flint and steel.
For the average giant slime that divides each time you hurt it. you can easily gain 20 or more slimeballs
As for fires set by red slimes. That makes them seriously dangerous. They would be impotent in water though. You don't go and try to kill creepers without arrows, do you? You can, but its very risky.
Red Slimes are way too overpowered, as you will be 90% set on fire per each kill of larger ones. Also their fire trail is totally annoyning and hard to avoid. Without at least 99+ buckets of water, i will simply not be able to fight them well (Unless, of course, i will spam them with arrows from fairly safe distance.).
Ice slimes are nice idea, but at other hand, they are mobile Snow farms. Just lure one into cage somewhere into forest, and you have fairly infinite source of Snow, without faintly passing 500 cubic meters or so to nearest Taiga biome in search of it.
Green Normal Slimes- no change. Drops green slime balls
Red fire Slimes- When they hop around, they leave a trail of fire. When you destroy a large slime(or bigger) it explodes with a fireball dealing fire damage and setting players and mobs on fire, and splits into smaller red slimes. Of course the fire slime is immune to fire. Drops Red Slime Balls.
Blue Ice Slimes- As they hop around. They leave snow on the ground where they have been. Large blue slimes create blocks of ice in the spot where it is killed, and splits into smaller blue slimes. Ice and snow will melt instantly if generated too near a torch or lava. Drops Blue Slimeballs
Slimeballs can be thrown(like eggs and snowballs)
Red Slimeballs can be thrown to start fires where they land. If thrown at a mob, it sets it on fire.
Blue Slimeballs, if thrown into water, freeze the water into ice. Or it creates snow if they hit land. If thrown at a mob, it freezes it solid until a torch or lava melts it.
Green Slimeballs cannot be thrown (or has no special effect if they can) and are used to craft red and blue together. Craft Red+Green+Blue. This makes an explosive block that can be placed like TNT, but doesn't destroy blocks. It only deals damage to mobs.
EDIT:Adding Spawn limits.
Blue Slimes only spawn in Snowy Biomes, both underground(all day and night) and on the surface,(only at night) light level less than 7(or whatever moonlight is)
Red Slimes spawn at Lava sources light level 14+
Green Slimes spawns are unchanged.
Blue Ice slimes...
Red slimeballs would be a long range version of flint and steel.
For the average giant slime that divides each time you hurt it. you can easily gain 20 or more slimeballs
As for fires set by red slimes. That makes them seriously dangerous. They would be impotent in water though. You don't go and try to kill creepers without arrows, do you? You can, but its very risky.
How so? Fire goes out very quickly on stone,
Though good point on the ice slimes.